In 1933 John Middleton Murry wrote his study titled William Blake. His stated aim was to 'elucidate the doctrine of William Blake, using only his written works as evidence.' His book evokes the man William Blake and his thought as well as any.
Murry uses this short quote from Auguries of Innocence to apply Blake's concept of 'states' to man's common experience of being angry.
Auguries of Innocence, (E 492)
"To be in a Passion you good may do;
But no good if a Passion is in you."
"The passion of Anger is a state; for the man who knows that it is a State, and keeps the Eternal Individual undisturbed and uncontaminated by it, Anger is a necessary instrument of life - a weapon against the enemies of life, and a means of purging the bosom of perilous stuff. Such anger is clean; one enters and leaves it as an alien thing; a flamelike visitation. But the anger that is in us, smolders and does not flame; it is a grudging resentment of a thwarted Selfhood, a state in which, because we do not know that it is a State, the Eternal Individual is lost.
From such an anger comes war. Forgiveness being the condition of the Eternal Individual, opposes its absolute veto to the corruption of pure wrath into corperal war. It refuses to allow righteous wrath to become the disguise of the appetite of the Selfhood for envy and hatred and vengeance." (Page 323)
At a critical point in the Four Zoas Los threatens to use the instrument of his anger against Urizen unless he repent and be redeemed from error's power. Los' anger against Urizen's error leads him to weep and seek to resume his human form.
Europe a Prophecy
Four Zoas, Night IX, Page 120, (E 390)
"My anger against thee is greater than against this Luvah
For war is energy Enslavd but thy religion
The first author of this war & the distracting of honest minds
Into confused perturbation & strife & honour & pride
Is a deceit so detestable that I will cast thee out
If thou repentest not & leave thee as a rotten branch to be burnd
With Mystery the Harlot & with Satan for Ever & Ever
Error can never be redeemd in all Eternity
But Sin Even Rahab is redeemd in blood & fury & jealousy
That line of blood that stretchd across the windows of the morning
Redeemd from Errors power. Wake thou dragon of the Deeps
Urizen wept in the dark deep anxious his Scaly form
To reassume the human & he wept in the dark deep"